1. Field of the Invention
The present invention relates to a method of evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp, an evaluation system for evaluating a basic curved surface for a reflecting mirror, and a computer-readable medium storing a program for enabling a computer to execute evaluation of a basic curved surface for a reflecting mirror to be applied to a vehicle lamp.
2. Related Background Art
A vehicle lamp comprises a light source, reflecting mirror for obtaining approximately parallel light from the light source, and a lens disposed in front of the reflecting mirror.
Recently, vehicles, incorporating the vehicle lamps, have been designed in their various shapes so that the shapes of vehicles become more attractive. This design requires the vehicle lamp to satisfy shape restrictions arising from conditions, such as the external shapes of the vehicles and a accommodation space required for the vehicle lamp, i.e., the requirement that the vehicle lamps have to be arranged in predetermined accommodation spaces with the attractive shapes of the vehicles being retained.
In the development of the vehicle lamps, it is necessary to determine the shape of the reflecting mirrors while taking such requirement into account. Thus, the reflecting mirrors of the vehicle lamps are composed of reflecting surface having, for example, a paraboloid of revolution or a multiple paraboloid, in order to obtain the desired reflection performance.
The lamps of automobiles have recently been required to achieve the shape restrictions that the lamps should be accommodated within the desired volume of the vehicles. In addition, the lamps have been required to achieve better optical performance than those in prior arts. To satisfy these requirements, the following configurations are adopted: (1) a reflecting mirror is composed of a plurality of reflecting surfaces; and (2) in determining the arrangement of the reflecting surfaces, a basic curved surface is determined to satisfy the shape restrictions and then the plurality of reflecting surfaces are disposed on this basic curved surface to form the reflecting mirror.
The present inventors have examined the design of this reflecting mirror and has discovered the following problems that occur when a reflecting mirror is provided with the improvement in the achievement of the requirements from the optical performance of the vehicle lamp while the requirement from the shape restrictions for the vehicle is satisfied. The inventors have also found that the optical performance of the reflecting mirror is separated into (1) the optical performance associated with the shape of the basic curved surface, and (2) the optical performance associated with the shapes and arrangements of the plurality of the reflecting surfaces. These optical performances of the reflecting mirror have been evaluated after the designing of the reflecting mirror proceeds to a particular stage of the design.
As the results of the inventors"" further examination for the two separate performances above, the inventors have discovered that these performances have the following characteristics: the evaluation of performance item (2) can not be made until the shape and arrangement of the individual reflecting surfaces are determined; and the performance item (1) can be, however, evaluated after the basic curved surface has been determined.
In other words, if we have an appropriate technique for evaluating the performance item (1), wasteful repetition in designing the reflecting mirror can be removed. In addition, since a accommodating space for a vehicle lamp is different from others, the basic curved surface to be designed for the vehicle lamp is also different from the others. If the optical performance of a basic curved surface can be evaluated by the use of such a technique at an early stage of a design flow, it will be possible to apply more appropriate feedback to this designing stage in order to obtain far better optical characteristics.
The above-described examinations have shown the following: what is desired is to develop a tool which can support the designing of basic curved surfaces that depends on the designers"" experiences; and it is also desired to evaluate optical performance at a predetermined design stage.
It is, therefore, an object of the present invention to provide as follows: a method of evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp; an evaluation system for evaluating a basic curved surface for a reflecting mirror; and a computer-readable medium storing a program for enabling a computer to execute evaluation of a basic curved surface for a reflecting mirror to be applied to a vehicle lamp.
The present inventors has made various examinations as to an evaluation method and an evaluation system, both of which are applicable to the evaluation of the optical performance of basic curved surfaces. The present invention will be constructed to have the following features. The present invention also has several aspects, as will be described below; a method of evaluating a basic curved surface, an evaluation system, a computer-readable medium storing a program.
One aspect of the present invention is a method of evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp. The method comprises the steps of: (a) entering light source information on a light source and design information indicative of the basic curved surface; and (b) displaying, on a display device, closed curved line data representative of one or more closed curved lines, the closed curved lines being included both in one or more planes intersecting a predetermined axis and in the basic curved surface. The predetermined axis is determined to extend in a direction in which light from the light source is to be reflected by the reflecting mirror, and passes through a light source position included in the light source information.
A computer program realizing this method includes a first input process provided so as to realize step (a) and a display process provided so as to realize step (b). This program enables a computer to execute evaluation of a basic curved surface for a reflecting mirror to be applied to a vehicle lamp. The program can be recorded on a computer-readable storage medium.
Another aspect of the present invention is an evaluation system for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp. The invention comprises: (1) a memory; (2) a display device; (3) first entering means for entering design information indicative of the basic curved surface and light source information on a light source to store the information in the memory; and (4) first transmitting means for transmitting, to the display device, closed curved line data representative of one or more closed curved lines, the closed curved lines being included both in the basic curved surface and in one or more planes intersecting a predetermined axis.
Since the curved lines are included both in the basic curved surface and in the planes intersecting the predetermined axis, the shape of the curved lines reflect the shape of the basic curved surface thereon. When this shape is displayed, evaluation information for the shape of the basic curved surface can be provided with respect to the direction of the predetermined axis.
The method of evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention can further comprises the steps of: (c) generating plane surface data indicative of the planes intersecting the predetermined axis; and (d) obtaining one or more lines of intersection of the generated planes and the basic curved surface according to the design information and the plane surface data to form the closed curved line data from the intersection lines.
The program recorded on the computer-readable storage medium can further include a plane surface generating process provided so as to realize the step (c), and intersection line generating process provided so as to realize the step (d).
The evaluation system for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention comprises (5) plane surface generating means for generating plane surface data indicative of the planes intersecting the predetermined axis, and (6) intersection line generating means for obtaining one or more lines of intersection of the planes and the basic curved surface on the basis of the design information and the plane surface data to form the closed curved line data from the intersection lines.
The closed curved line data can be obtained by generating the plane surface data and then obtaining the lines of intersection of the planes and the basic curved surface.
The method of evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention further comprises the steps of (e) entering plane surface information, the information defining at least one of the following: the number of the planes; and the distance between the planes. The plane surface data is defined to provide a plurality of planes, perpendicular to the axis, which are arranged with the distance and the number defined by the plane surface information.
The program recorded on the storage medium further includes a second input process provided so as to realize the step (e).
An evaluation system for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention further comprises (7) second entering means for entering plane surface information, the plane surface information defining at least one of the following: the distance between the planes; and the number of the planes.
By defining the distance between plane surfaces to be generated, it is possible to designate the pitch of lines of intersections for representing the schematic shape of the basic curved surface. By defining the number of plane surfaces, it is possible to designate the number of lines of intersections for representing the schematic shape of the basic curved surface. In this manner, it is possible to designate the parameters required to show the schematic shape of the basic curved surface. For example, the planes can be generated to be disposed in parallel with one another. These closed curved lines can show the schematic shape of the basic curved surface by a technique similar to contours.
The method for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention further comprises the step of (f) erasing the display of the closed curved line data from the display device. The method for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention further comprises the step of (g) repeating steps (b) to (f).
The program recorded on the storage medium further includes an erasing process provided so as to realize the step (f). The program recorded on the storage medium further includes a repetition process arranged to realize the step (g).
The evaluation system for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention further includes (8) erasure means for erasing the display of the closed curved line data from the display device.
After the closed curved line data has been erased, another closed curved line data can be displayed on the display. Accordingly, it is possible to repeatedly evaluate the schematic shape of the basic curved surface.
In the method for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp according to the present invention, step (b) includes a step of displaying the closed curved line data in such a manner that the closed curved line data is superposed on the basic curved surface displayed on the display device.
The program recorded on the storage medium includes a process provided so as to display the closed curved line data such that the closed curved lines is superposed on the basic curved surface displayed on the display device.
The evaluation system for evaluating a basic curved surface for a reflecting mirror to be applied to a vehicle lamp can further comprises (h) second transmitting means for transmitting, to the display device, data containing the design information and corresponding to the basic curved surface.
By displaying the closed curved line data such that the closed curved line data is superposed on the basic curved surface, it is possible to represent the closed curved line data in association with the basic curved surface.
Another aspect of the present invention is a method of designing a basic curved surface for a reflecting mirror to be used in a vehicle lamp. The invention comprises the steps of: (i) determining a basic curved surface defining the reflecting mirror, on the basis of the following: shape restriction conditions to define a accommodation space which can be occupied by the reflecting mirror; and the position restriction conditions to define the position of a light source in the vehicle lamp; (ii) displaying, on a display device, closed curved line data representative of one or more closed curved lines; and (iii) making evaluation of the reflection performance of the basic curved surface on the basis of the displayed closed curved lines. The closed curved lines are included both in the basic curved surface and in one or more planes intersecting an axis. The axis extends in a direction in which light from the light source is to be reflected by the reflecting mirror. The axis also passes through a position at which the light source is to be arranged.
By displaying the closed curved lines, the schematic shape of the basic curved surface can be represented. Accordingly, it is possible to evaluate the reflection performance of the basic curved surface as a whole. This evaluation is made as to whether the basic curved surface is appropriate for use in the vehicle lamp.
The method of designing a basic curved surface for a reflecting mirror to be used in a vehicle lamp according to the present invention can further include the step of (iv) executing the steps (i) to (iii) in response to an evaluation indicating that the basic curved surface is inappropriate for use in the vehicle lamp. This evaluation method provides a sequence of evaluation that allows the basic curved surface to exhibit a reflection performance closer to a predetermined level thereof.
In the method of designing a basic curved surface for a reflecting mirror to be used in a vehicle lamp according to the present invention, the planes can be arranged to be spaced apart at an interval of a first distance. Accordingly, the shape of the basic curved surface can be understood as a whole from the closed curved line data provided at the equal interval on the display.
The method of designing a basic curved surface for a reflecting mirror to be used in a vehicle lamp according to the present invention further comprises the steps of: (v) erasing a displayed image of the closed curved line data from the display device, (vi) generating second plane surface data indicative of a plurality of planes which are arranged at an interval or a second distance smaller than the first distance, the second planes intersecting a predetermined axis, (vii) generating another closed curved line data indicative of lines of intersections of the planes and the basic curved surface according to design information and the second, plane surface data, and (viii) displaying the other closed curved line data on the display device.
Since it is possible to display the other closed curved line data after the displayed closed curved line data has been erased, the basic curved surf ace can be evaluated on a step-by-step basis. Accordingly, it is possible to make accurate evaluation of the part of the shape, and it is also possible to make schematic evaluation of the whole of the shape.
In the method of designing a basic curved surface for a reflecting mirror to be used in a vehicle lamp according to the present invention, step (ii) includes the step of displaying the closed curved line data so as to superpose the closed curved lines on the basic curved surface.
By displaying the closed curved line data so as to superpose the closed curved lines on the basic curved surface, the closed curved line data is visualized in association with the basic curved surface. Therefore, the evaluation can be made while the closed curved line data is compared with the shape conditions of the reflecting mirror.